#teapolyphenols

What is Tea Polyphenol？

Tea polyphenol (TPs) is a class of polyhydroxyphenols and main chemical components in tea, also known as “tea tannins.” They are yellowish to brownish-yellow crystals or powders. The content in tea is generally 18-36% (dry weight).

The main components of tea polyphenol

The main components of tea polyphenols include flavonols, flavonoids, tea pigments, and phenolic acids. Flavanols catechins are the most important, accounting for about 70-80% of the total amount of polyphenols. Except for phenolic acid, other compounds have 2-phenyl-4H-chromene as the main body. The basic structure so collectively referred to as flavonoids.

The solubility of flavonoids varies significantly due to their different structures, so the solubility of tea polyphenols varies among other types. However, tea polyphenols generally are readily soluble in ethyl acetate, acetone, methanol, ethanol, and water, slightly soluble in oil, and insoluble in petroleum ether, benzene, and chloroform.

Properties of tea polyphenol

Tea polyphenols have phenolic hydroxyl groups in their molecules, which can dissociate H+, so they are acidic. Tea polyphenols are easily oxidized, especially in an aqueous solution or polyphenol oxidase. The phenolic hydroxyl is dissociated, generating oxygen anion, further losing electrons, and producing o-quinone, which can seize hydrogen from other substances and be reduced to phenol and can also polymerize to produce the reddish-brown polymer.

Tea polyphenols have phenolic hydroxyl groups in their molecules, which can dissociate H+, so they are acidic. Tea polyphenols are easily oxidized, especially in an aqueous solution or polyphenol oxidase. The phenolic hydroxyl groups are dissociated to generate oxygen anions, further lose electrons, and create o-quinone, which can take hydrogen from other substances and be reduced to phenols. Polymerization can occur to produce reddish-brown polymers.

Tea polyphenol has an astringent, bitter taste, and strong astringency. They are the main substances that make up the astringent taste of tea soup and produce saliva and sweetness. Astringency is an essential sensory property of tea soup taste and an important factor affecting tea quality and consumer acceptance.

Therefore, tea polyphenol significantly contributes to tea taste and is closely related to taste concentration. Moreover, it is easily oxidized to form tea pigments, the main components of tea soup color.

Green tea extract polyphenols In Weight loss Products

Many say they want to lose weight, which has almost become a national topic. Most weight loss products contain plant or drug ingredients, and some contain green tea catechins. Today, we will discuss the long-term consumption of green tea extract.

Catechins are an active substance in green tea extract. It can reduce our blood fat and body fat, and if we take green tea extract to lose weight when we lose weight, it is not easy to rebound. Green tea extract often uses as a food additive and is widely used in various foods we eat daily. If I take green tea extract for a long time, it may be good for my health and clean up the waste in my body, but it will also have some harmful effects.

What is catechin?

Catechin is the essential tea polyphenol, and tea polyphenols account for about 75%-80% of all kinds of tea, giving the tea a bitter taste. Due to the difference in the production process, the content of catechins in various tea is different, and the content of catechins in unfermented green tea is the highest.

Catechins mainly contain four categories: EGCG (epigallocatechin gallate) is the highest content in tea, and many studies with the intake of EGCG instead of catechins.

The report of green tea catechins from EFSA

EFSA has assessed the safety of green tea catechins from dietary sources, following concerns regarding their possible harmful effects on the liver. EFSA concluded that catechins from green tea infusions and similar drinks are generally safe. However, catechin doses at or above 800 mg/day may pose health concerns when taken as food supplements.

For green tea infusions, EFSA’s experts concluded that there is no indication of liver damage even after high consumption and that the few cases of liver damage reported in humans are likely due to rare and unpredictable reactions. Experts, therefore, considered catechins from green tea infusions brewed with hot water, and instant and ready-to-drink green tea beverages with similar catechin content, as generally safe.

Conclusion

In a word, drinking green tea is fine. We should be alert to supplements containing concentrated green tea extracts and weight loss products.